<template>
    <div ref="dropdown" :class="rootClasses" class="dropdown dropdown-menu-animation" @mouseleave="isHoverable = false">
        <div v-if="!inline" ref="trigger" :tabindex="disabled ? false : triggerTabindex" aria-haspopup="true"
            class="dropdown-trigger" @click="onClick" @mouseenter="onHover" @contextmenu.prevent="onContextMenu"
            @focus.capture="onFocus">
            <slot :active="isActive" name="trigger" />
        </div>

        <transition :name="animation">
            <div v-if="isMobileModal" v-show="isActive" :aria-hidden="!isActive" class="background" />
        </transition>
        <transition :name="animation">
            <div v-show="(!disabled && (isActive || isHoverable)) || inline" ref="dropdownMenu" v-trap-focus="trapFocus"
                :aria-hidden="!isActive" :style="style" class="dropdown-menu">
                <div :aria-modal="!inline" :role="ariaRole" :style="contentStyle" class="dropdown-content">
                    <slot />
                </div>
            </div>
        </transition>
    </div>
</template>

<script>
import trapFocus from 'buefy/src/directives/trapFocus'
import config from 'buefy/src/utils/config'
import {createAbsoluteElement, isCustomElement, removeElement, toCssWidth} from 'buefy/src/utils/helpers'
import ProviderParentMixin from 'buefy/src//utils/ProviderParentMixin'

const DEFAULT_CLOSE_OPTIONS = ['escape', 'outside']

export default {
    name: 'CDropdown',
    directives: {
        trapFocus
    },
    mixins: [ProviderParentMixin('dropdown')],
    props: {
        value: {
            type: [String, Number, Boolean, Object, Array, Function],
            default: null
        },
        disabled: Boolean,
        inline: Boolean,
        scrollable: Boolean,
        maxHeight: {
            type: [String, Number],
            default: 200
        },
        position: {
            type: String,
            validator(value) {
                return [
                    'is-top-right',
                    'is-top-left',
                    'is-bottom-left',
                    'is-bottom-right',
                    'is-top',
                    'is-bottom',
                    'is-right',
                    'is-left'
                ].indexOf(value) > -1
            }
        },
        triggers: {
            type: Array,
            default: () => ['click']
        },
        mobileModal: {
            type: Boolean,
            default: () => {
                return config.defaultDropdownMobileModal
            }
        },
        ariaRole: {
            type: String,
            validator(value) {
                return [
                    'menu',
                    'list',
                    'dialog'
                ].indexOf(value) > -1
            },
            default: null
        },
        animation: {
            type: String,
            default: 'fade'
        },
        multiple: Boolean,
        trapFocus: {
            type: Boolean,
            default: () => {
                return config.defaultTrapFocus
            }
        },
        closeOnClick: {
            type: Boolean,
            default: true
        },
        canClose: {
            type: [Array, Boolean],
            default: true
        },
        expanded: Boolean,
        appendToBody: Boolean,
        appendToBodyCopyParent: Boolean,
        triggerTabindex: {
            type: Number,
            default: 0
        }
    },
    data() {
        return {
            selected: this.value,
            style: {},
            isActive: false,
            isHoverable: false,
            // eslint-disable-next-line vue/no-reserved-keys
            _bodyEl: undefined // Used to append to body
        }
    },
    computed: {
        rootClasses() {
            return [this.position, {
                'is-disabled': this.disabled,
                'is-hoverable': this.hoverable,
                'is-inline': this.inline,
                'is-active': this.isActive || this.inline,
                'is-mobile-modal': this.isMobileModal,
                'is-expanded': this.expanded
            }]
        },
        isMobileModal() {
            return this.mobileModal && !this.inline
        },
        cancelOptions() {
            return typeof this.canClose === 'boolean'
                ? this.canClose
                    ? DEFAULT_CLOSE_OPTIONS
                    : []
                : this.canClose
        },
        contentStyle() {
            return {
                maxHeight: this.scrollable ? toCssWidth(this.maxHeight) : null,
                overflow: this.scrollable ? 'auto' : null
            }
        },
        hoverable() {
            return this.triggers.indexOf('hover') >= 0
        }
    },
    watch: {
        /**
        * When v-model is changed set the new selected item.
        */
        value(value) {
            this.selected = value
        },

        /**
        * Emit event when isActive value is changed.
        */
        isActive(value) {
            this.$emit('active-change', value)
            this.handleScroll()
            if (this.appendToBody) {
                this.$nextTick(() => {
                    this.updateAppendToBody()
                })
            }
        },

        isHoverable(value) {
            if (this.hoverable) {
                this.$emit('active-change', value)
            }
        }
    },
    methods: {
        handleScroll() {
            if (typeof window === 'undefined') return

            if (this.isMobileModal) {
                if (this.isActive) {
                    document.documentElement.classList.add('is-clipped-touch')
                } else {
                    document.documentElement.classList.remove('is-clipped-touch')
                }
            }
        },

        /**
         * Click listener from DropdownItem.
         *   1. Set new selected item.
         *   2. Emit input event to update the user v-model.
         *   3. Close the dropdown.
         */
        selectItem(value) {
            if (this.multiple) {
                if (this.selected) {
                    if (this.selected.indexOf(value) === -1) {
                        // Add value
                        this.selected = [...this.selected, value]
                    } else {
                        // Remove value
                        this.selected = this.selected.filter((val) => val !== value)
                    }
                } else {
                    this.selected = [value]
                }
                this.$emit('change', this.selected)
            } else {
                if (this.selected !== value) {
                    this.selected = value
                    this.$emit('change', this.selected)
                }
            }
            this.$emit('input', this.selected)
            if (!this.multiple) {
                this.isActive = !this.closeOnClick
                if (this.hoverable && this.closeOnClick) {
                    this.isHoverable = false
                }
            }
        },

        /**
        * White-listed items to not close when clicked.
        */
        isInWhiteList(el) {
            if (el === this.$refs.dropdownMenu) return true
            if (el === this.$refs.trigger) return true
            // All chidren from dropdown
            if (this.$refs.dropdownMenu !== undefined) {
                const children = this.$refs.dropdownMenu.querySelectorAll('*')
                for (const child of children) {
                    if (el === child) {
                        return true
                    }
                }
            }
            // All children from trigger
            if (this.$refs.trigger !== undefined) {
                const children = this.$refs.trigger.querySelectorAll('*')
                for (const child of children) {
                    if (el === child) {
                        return true
                    }
                }
            }
            return false
        },

        /**
        * Close dropdown if clicked outside.
        */
        clickedOutside(event) {
            if (this.cancelOptions.indexOf('outside') < 0) return
            if (this.inline) return

            const target = isCustomElement(this) ? event.composedPath()[0] : event.target
            if (!this.isInWhiteList(target)) this.isActive = false
        },

        /**
         * Keypress event that is bound to the document
         */
        keyPress({ key }) {
            if (this.isActive && (key === 'Escape' || key === 'Esc')) {
                if (this.cancelOptions.indexOf('escape') < 0) return
                this.isActive = false
            }
        },

        onClick() {
            if (this.triggers.indexOf('click') < 0) return
            this.toggle()
        },
        onContextMenu() {
            if (this.triggers.indexOf('contextmenu') < 0) return
            this.toggle()
        },
        onHover() {
            if (this.triggers.indexOf('hover') < 0) return
            this.isHoverable = true
        },
        onFocus() {
            if (this.triggers.indexOf('focus') < 0) return
            this.toggle()
        },

        /**
        * Toggle dropdown if it's not disabled.
        */
        toggle() {
            if (this.disabled) return

            if (!this.isActive) {
                // if not active, toggle after clickOutside event
                // this fixes toggling programmatic
                this.$nextTick(() => {
                    const value = !this.isActive
                    this.isActive = value
                    // Vue 2.6.x ???
                    setTimeout(() => (this.isActive = value))
                })
            } else {
                this.isActive = !this.isActive
            }
        },

        updateAppendToBody() {
            const dropdown = this.$refs.dropdown
            const dropdownMenu = this.$refs.dropdownMenu
            const trigger = this.$refs.trigger
            if (dropdownMenu && trigger) {
                // update wrapper dropdown
                const dropdownWrapper = this.$data._bodyEl.children[0]
                dropdownWrapper.classList.forEach((item) => dropdownWrapper.classList.remove(item))
                dropdownWrapper.classList.add('dropdown')
                dropdownWrapper.classList.add('dropdown-menu-animation')
                if (this.$vnode && this.$vnode.data && this.$vnode.data.staticClass) {
                    dropdownWrapper.classList.add(this.$vnode.data.staticClass)
                }
                this.rootClasses.forEach((item) => {
                    // skip position prop
                    if (item && typeof item === 'object') {
                        for (let key in item) {
                            if (item[key]) {
                                dropdownWrapper.classList.add(key)
                            }
                        }
                    }
                })
                if (this.appendToBodyCopyParent) {
                    const parentNode = this.$refs.dropdown.parentNode
                    const parent = this.$data._bodyEl
                    parent.classList.forEach((item) => parent.classList.remove(item))
                    parentNode.classList.forEach((item) => {
                        parent.classList.add(item)
                    })
                }
                const rect = trigger.getBoundingClientRect()
                let top = rect.top + window.scrollY
                let left = rect.left + window.scrollX
                if (!this.position || this.position.indexOf('bottom') >= 0) {
                    top += trigger.clientHeight
                } else {
                    top -= dropdownMenu.clientHeight
                }
                if (this.position && this.position.indexOf('left') >= 0) {
                    left -= (dropdownMenu.clientWidth - trigger.clientWidth)
                }
                if (this.position && this.position.indexOf('is-right') >= 0) {
                    console.log('is-right');
                    top += 0
                    left -= 0
                }

                this.style = {
                    position: 'absolute',
                    top: `${top}px`,
                    left: `${left}px`,
                    zIndex: '99',
                    width: this.expanded ? `${dropdown.offsetWidth}px` : undefined
                }
            }
        }
    },
    mounted() {
        if (this.appendToBody) {
            this.$data._bodyEl = createAbsoluteElement(this.$refs.dropdownMenu)
            this.updateAppendToBody()
        }
    },
    created() {
        if (typeof window !== 'undefined') {
            document.addEventListener('click', this.clickedOutside)
            document.addEventListener('keyup', this.keyPress)
        }
    },
    beforeDestroy() {
        if (typeof window !== 'undefined') {
            document.removeEventListener('click', this.clickedOutside)
            document.removeEventListener('keyup', this.keyPress)
        }
        if (this.appendToBody) {
            removeElement(this.$data._bodyEl)
        }
    }
}
</script>

<style lang="scss" scoped>
.dropdown.is-right .dropdown-menu {
    top: 0;
    left: 100%;
}
</style>